There is more than one artist with this name:
1) Manassas was a seventies American rock band formed by Stephen Stills in 1971.
2) Manassas was a musical project by English musician Shaun Blezard that ran from 2001 to 2005
1) Manassas was a seventies American rock band formed by Stephen Stills in 1971. The nucleus of the band had already backed Stills on his July 1971 album Stephen Stills 2, and in May 1972, the double-LP Manassas was released. Down The Road was released in 1973 and in September of that year the band split.